Magnetic resonance imaging findings in children with intractable epilepsy compared to children with medical responsive epilepsy

Objective Epilepsy is a common brain disorder characterized by a persistent tendency to develop seizures in neurological, cognitive, and psychological contents. Magnetic Resonance Imaging (MRI ) is a neuroimaging test facilitating the detection of structural epileptogenic lesions. This study aimed to compare the MRI findings between patients with intractable and drug-responsive epilepsy. Material & Methods This case-control study was conducted from 2007 to 2019. The research population encompassed all 1-16-year-old patients with intractable epilepsy referred to the Shafa Neuroscience Center (n=72) (a case group) and drug-responsive patients referred to the pediatric neurology clinic of Baqiyatallah Hospital (a control group). Results There were 72 (23.5%) patients in the intractable epilepsy group and 200 (76.5%) patients in the drug-responsive group. The participants’ mean age was 6.70± 4.13 years, and there were 126 males and 106 females in this study. Normal brain MRI was noticed in 21 (29.16%) patients in the case group and 184 (92.46%) patients in the control group. Neuronal migration disorder (NMD) was also exhibited in 7 (9.72%) patients in the case group and no patient in the control group. There were hippocampal abnormalities and focal lesions (mass, dysplasia, etc.) in 10 (13.88%) patients in the case group and only 1 (0.05%) patient in the control group. Gliosis and porencephalic cysts were presented in 3 (4.16%) patients in the case group and no patient in the control group. Cerebral and cerebellar atrophy was revealed in 8 (11.11%) patients in the case group and 4 (2.01%) patients in the control group. Corpus callosum agenesis, hydrocephalus, brain malacia, and developmental cyst were more frequent in the case group; however, the difference between the groups was not significant. Conclusion The MRI findings such as hippocampal abnormalities, focal lesions (mass, dysplasia), NMD, porencephalic cysts, gliosis, and atrophy are significantly more frequent in children with intractable epilepsy than in those with drug-responsive epilepsy.


Introduction
Seizures are attacks of the nervous system, resulting in sudden and reversible changes in mental status or somatosensory function, and tend to have a stereotypical and repetitive nature.
Epilepsy is a brain disorder characterized by a persistent tendency to develop seizures in the neurobiological, cognitive, and psychological contexts. It is a well-known disorder of ancient times and dates back to the Stone Age. About 4-5% of children experience at least one seizure (febrile or afebrile) during the first sixteen years, 3% of which are caused by epilepsy (1,2).
The clinical diagnosis of epilepsy requires at least one unprovoked seizure with a second seizure attack or abnormal EEG and sufficient clinical information to indicate a continuing susceptibility to recurrence.
The duration of epilepsy attacks varies from a few seconds to a few minutes (rarely a few hours), abruptly terminating and gradually returning to baseline. There may be warning signs before the attack, including Aura or decreasing consciousness, and after the attack, called postictal situation (1,2 After fifteen years, new anticonvulsants (namely Lamotrigine and Gabapentin) were introduced, and many new drugs were then introduced a few years later. The new generation of antiepileptic drugs is often used to treat refractory seizures (7,8).
In 70% of cases, epileptic seizures are completely controlled with one drug. In 10% of the cases, the severity and frequency of attacks decrease, and in 20% of such patients, seizures remain uncontrollable and resistant despite appropriate pharmacological treatment (9,10).
Although there has been significant progress in the treatment of epilepsy during the last few decades, a highly remarkable percentage of patients resist drug therapy. Studying intractable epilepsy is important since the treatment is complicated.
According to the published literature on the significance of the MRI imaging in epileptic patients, there should be investigations to detect whether it is helpful in the differential diagnosis of refractory epilepsy and drug-responsive epilepsy (5). Accordingly, the present study aimed to compare the MRI findings of patients with intractable and drug-responsive epilepsy.

Patients
The patients were studied in two groups (namely medical responsive epilepsy and intractable epilepsy) from July 2007 to August 2019.
Seventy-two (23.5%) patients were included in the intractable epilepsy group, and 200 (76.5%) patients were in the drug-responsive group. One case in drug-responsive was excluded from the study due to refusing to cooperate in the study.
The participants' mean age was 6.70± 4.13. Table 1 presents the mean age and gender of each group. In this study, there were 126 males and 106 females.
The frequency of the male gender was higher than the female; however, the difference was not significant. Finally, the analysis of age and gender revealed no significant difference between the two groups and also between cases with normal and abnormal MRI findings in the two groups. Table 2 shows the MRI findings in both groups. Signal intensities were higher in the brain white matter of the drug-responsive group than in the intractable epilepsy group (3.01% vs. 0.05%); however, the difference was not statistically significant (p = 0.679).

Findings
such as developmental cyst, hydrocephalus, brain malacia, and corpus callosum agenesis were insignificantly more frequent in the case group. However, porencephalic cyst and gliosis were significantly higher in the case group (